The situation 'Ontology < Logic' appears typically in description logic,
which assumes concepts to be atomic, i.e. description logic appears more like
a propositional calculus than a predicate calculus, even if description logic is embeddable
into first-order logic. However, as predicates are mostly missing,
concepts appear basically as constants in the underlying signature of the logic.
Furthermore, description is not a full logic as inference calculi are ad hoc and not really
integrated into the logic as typically seen in formal logic.
This makes the description logic obviously much less expressive,
and ontology based on description logic approaches leads at most to associative structures
and relation based hierarchies.

In fact, in description logic
the underlying assumption is very much like having one single type for 'concept', and having
a huge number of atomic concepts appearing as constants of type 'concept',
e.g., as seen in the medical terminology
SNOMED CT by IHTSDO.
SNOMED CT now leans on the RDF and
OWL adaptations of
EL++
as a variant of description logic for its ontology developments.
A correction of this situation is provided in
Fuzzy Terms.

The simplicity of description logic is certainly intentional,
as the motivation of using such a 'partial logic' is given
by the need to capture vocabulary, terminology and thesauri more than aiming at explicit
reasoning with these concepts and structures. However, in social and health care, this lack of capability
to provide reasoning mechanisms e.g. for utility in clinical guidelines social decision-making,
is not entirely well-understood.

The HL7 approach to standards still avoid adaptation
of a particular logic for empowering its potential epistemological structures. Mixing HL7 and SNOMED CT is not advisable,
and indeed, national authorities tend to choose one of these over the other as a national recommendation
for developing social and health care ontology.

In general, the question of suitability of particular logics for ontology is quite subtle.
EL++ works well in OWL and in the domain of web ontology, but obviously 'web ontology' is less than 'ontology' roughly
in the same fashion as 'summer house' is less than 'house', and it is rather brave to conjecture that
web ontology and medical ontology are related to an extent that choices of underlying logics follow
hand-in-hand. The future will tell whether or not this strategic choice is optimal.

These are the reasons why our
answer to the above question is Ontology = Logic, and that
ontology logic should not necessarily be restricted.
One of the objectives of our example and case developments is to provide more and logically
deeper insight into ontology e.g. as affecting guidelines and repositories.